Drill.



UNITED STATES DONATO CEDRONE, OF NEW YORK, N.. Y.

DRILL.

i specification of Letters Patent.

Patented Oct. 20, 1914.

.Application le October 25, 1913. Serial Ho. 797,832.

To all I whom it may concem Be 1t ,known that I, DoNA'ro CEDRoNE, a

citizen of Italy, residing at New York, in

' the county of Newl York and State of New York, have invented certain new and Usefull Improvements in Drills; and I dohereby decl'are the .following to be a full, clear, and exact description of the invention, such as will enable others skilled in theart' to which it appertains to make and use the 4 Saule.

' 14 which stands radial to the end of the drill This invention relates to drill bits and has for an object to' provide an improved form of a bit to present a circular cutting action when the drill is beingV used. i VFurther objects will be -apparent from' the following specification, appended claim and drawings in which:

Figure 1 is a plan view of one form of the bit. Fig. 2 is iaflperspective view thereof. Fig. 3 is a longitudinal sectional view and, Fig. 4 is a perspective view of a modified form.

Referring to thev drawing in which similar reference numerals refer to similar parts throughout the several views, there is shown a shank 10 which has the cutting end thereof enlarged as at 11, and having V shaped grooves 12 formed in the sides of the enlarged portion. The V shaped grooves 12 form radially dis osed claws which have the edges thereof sharpened as shown at 13. This cutting edge is substan-ti'ally arcuate in side elevation and in end view. The end of each with these claws is formed of a rib and is sharpened to the desired degree. This rib produces flaring .faces 15 of which the portions between the cutting edges 13 and 14 are concaved as shown.

. In the larger drills or those intended for lmachine driving, the drill is solid and the l ridges formed by the cutting edges 14 meet at a common center, while the-form shown in Fig. 4 has a central passage 16 through "the shank and bit, to provide a conduit for water or air. T e cutting edges are approximately in line with the line formed by the cutting edges of the sides 15 opposite thereto. The grooves 12 permit passage of the dust and chips formed in the cutting past the enlarged portion 11.

1I lfaving thus described my invention I c aim:

'The herein described bit comprising a shank enlargedtoward its cutting end and provided with' three V-shaped longitudinal grooves in its Sides growing deeper toward said end and there producing interposed claws, the forward corner of each claw being struck on a single arc in both side elevation and end view and sharpened to a cutting In testimon whereof I aflix my Signature i in presence o two witne'sses.

DONATO CEDRONE.

Witnesses:

MAE PnnnY, GEORGE L. THoRN. 

